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TPS53319: VIN current at no load

Kazuhiko Hirano
Genius 14918 points
Part Number: TPS53319

Tool/software:

Hello,

My customer measured VIN current on their board at the following condition, and it was ~66mA.
They would like to know if this 66mA is a reasonable value or not. Could TI show the typical VIN current at their conditions from design point of view or TI lab test value?

Mode=FCCM
VIN=12V
Vout=5V, no load(Iout=0A)
fSW=800KHz


Best regards,

K.Hirano

  • 0
    TI__Guru 56795 points

      

    Kazuhiko Hirano said:
    They would like to know if this 66mA is a reasonable value or not.

    Given that they are operating at 800kHz switching frequency in Forced Continuous Conduction Mode (FCCM) 66mA of input current is not unreasonable.

    Most of this current is the power for turning the MOSFETs ON and OFF each switching cycle, with lessor amounts for the switching losses of the transitions of the MOSFET and the conduction losses of the ripple current through the inductor and MOSFETs.

    They could significantly reduce this input current by operating in discontinuous "auto-skip" mode at light load.  This would reduce the switching frequency at light load and provide the ≈ 1mA average input current at no load.